@theducks - it is an idea that I believe "could" be done but I don't think it would be worth the effort of coding it up. Changing domain name is a pretty drastic event that is unlikely to happen very often, versus the more likely occurrence of when they restyle the website which is what causes the serious developer pain.

To expand on what you said, when moved to a new domain, websites are often changed to the point that the old code for parsing fails.